1. Field of the Invention
The field of the invention relates generally to programmable logic controller (PLC) based industrial control systems. More particularly, the invention relates to certain new and useful advances for input/output (I/O) modules and application specific integrated circuitry (ASIC) for driving a plurality of I/O functions.
2. Description of Related Art
A complex automated industrial system requires an organized hierarchy of controller systems to function. Generally, the hierarchy includes a Human Machine Interface (HMI) linked to programmable logic controllers (PLC) via a non-time-critical communications system (e.g. Ethernet). At the bottom of the control chain is a central processing unit (CPU) which has a subsystem (i.e., a bus) that transfers data between components inside the CPU and links the PLCs to the delta point of a peripheral that performs certain tasks and gather data, such as sensors, actuators, electric motors, console lights, switches, valves and contactors.
PLCs have the facility for extensive input/output (I/O) arrangements, typically held in PLC racks, which connect the PLC to sensors and actuators. The I/O arrangements may be built into a simple PLC, or the PLC may have external I/O modules attached to a computer network that plugs into the PLC through the PLC rack. The PLC rack typically comprises a predetermined number of slots, which are dedicated modules for a single function
Typically, a multitude of different electrical parts and integrated circuits are used to drive each one of the specific input/output configurations. When users install I/O modules into PLC racks, they individually wire each point that is being controlled to the specific I/O point. Generally, each point in the module is individually wired to connect the I/O module to the machine interface, and a cable customized to the specifically wired I/O module is utilized. Therefore, to connect different machine interfaces to the same I/O module, multiple customized connector cables are utilized. Furthermore, PLC control racks only have a certain number of slots, and extending each PLC rack can prove to be expensive and time consuming. While smaller industrial systems may only require between 16 and 32 points, large systems may comprise ten-thousand to thirty-thousand points, at which point it becomes unfeasible to store enough modules to control each function. Over the past decades this has resulted in a large number of fragmented product offerings that are difficult to source, maintain and support.
Systems have been developed that attempt to alleviate this problem. For example, a system for configuring a reconfigurable I/O (RIO) device to perform a function in response to user requirements has been provided. A configuration generation program generates a hardware configuration program based on the user input, and the hardware configuration program is usable to configure a device to perform the function, where the device includes a programmable hardware element and one or more fixed hardware resources coupled to the programmable hardware element.
Another example, includes a soft I/O system has been developed in which any I/O connector pin of the soft-I/O can be an input, output, power or ground such that the number of switches and channels can be reduced.
However, the above described ad hoc approaches are not useful in industrial settings, particularly where high-level electronic noise is prevalent. Moreover, the above-described approaches require additional noise suppression components which can be costly and are not conducive to large scales.
Accordingly, to date, no suitable hardware based apparatus or method processing and driving a plurality of I/O functions suitable for industrial environments exists.